Although locomotives are always fitted with compressed air braking systems, a portion of the rolling stock available on some railway networks is still fitted with vacuum brakes while the remainder has compressed air brakes. The locomotives in use on these networks must therefore be capable of providing braking for trains fitted with vacuum brakes or for trains fitted with compressed air brakes. Since the flow rate of available vacuum pumps is limited, it is sometimes necessary to provide a locomotive with two vacuum pumps in addition to a compressor. This means that a locomotive needs three piston apparatuses to be installed thereon, which can give rise to problems of mass, of bulk, and of cost. These three apparatuses together with associated means are bulky, and they become difficult to drive using pulleys and belts within the restricted space available.
The object of the present invention is to provide a feed circuit for railway braking systems which can be used equally well with trains made up of rolling stock braked by compressed air or with trains made up of rolling stock braked by vacuum, with said feed circuit being more compact and lighter than prior circuits, and additionally reducing vibration and reducing maintenance operations.